| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [pron] could [adv] [vb infin] | 771 |
|
| 2 | [vb past] they [modal v] [adv] [vb infin] | 223 |
|
| 3 | [verb] they could [adv] [vb infin] | 163 |
|
| 4 | [vb past] they could [adv] [verb] | 100 |
|
